H2O vapor as a processing gas for crust, resist, and residue removal for post ion implant resist strip

ABSTRACT

H 2 O vapor is used as a processing gas for stripping photoresist material from a substrate having a patterned photoresist layer previously used as an ion implantation mask, wherein the patterned photoresist layer is defined by a photoresist crust covering a bulk photoresist portion. Broadly speaking, the H 2 O vapor is demonstrated to more efficiently strip the photoresist material having a cross-linked photoresist crust without causing the photoresist crust to pop and without causing the bulk photoresist to be undercut. Thus, H 2 O vapor provides a safe, efficient, and economical processing gas for stripping photoresist material having a photoresist crust resulting from an ion implantation process.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to semiconductorfabrication, and more particularly, to methods and apparatuses for usingH₂O vapor as a processing gas for stripping photoresist material from asubstrate having a patterned photoresist layer previously used as an ionimplantation mask.

[0003] 2. Description of the Related Art

[0004] During semiconductor fabrication, integrated circuits are createdon a semiconductor wafer (“wafer”) composed of a material such assilicon. To create the integrated circuits on the wafer, it is necessaryto fabricate a large number (e.g., millions) of electronic devices suchas resistors, diodes, capacitors, and transistors of various types.Fabrication of the electronic devices involves depositing, removing, andimplanting materials at precise locations on the wafer. A process calledphotolithography is commonly used to facilitate deposition, removal, andimplantation of materials at precise locations on the wafer.

[0005] In the photolithography process, a photoresist material is firstdeposited onto the wafer. The photoresist material is then exposed tolight filtered by a reticle. The reticle is generally a glass plate thatis patterned with exemplary feature geometries that block light frompassing through the reticle. After passing through the reticle, thelight contacts the surface of the photoresist material. The lightchanges the chemical composition of the exposed photoresist material.With a positive photoresist material, exposure to the light renders theexposed photoresist material insoluble in a developing solution.Conversely, with a negative photoresist material, exposure to the lightrenders the exposed photoresist material soluble in the developingsolution. After the exposure to the light, the soluble portions of thephotoresist material are removed, leaving a patterned photoresist layer.

[0006] The wafer is then processed to either deposit, remove, or implantmaterials in the wafer regions not covered by the patterned photoresistlayer. After the wafer processing, the patterned photoresist layer isremoved from the wafer in a process called photoresist stripping. It isimportant to completely remove the photoresist material during thephotoresist stripping process because photoresist material remaining onthe wafer surface may cause defects in the integrated circuits. Also,the photoresist stripping process should be performed carefully to avoiddamaging the electronic devices present on the wafer.

[0007] As with many other wafer fabrication processes, an ionimplantation process utilizes photolithography to protect specific areasof the wafer where ion implantation is not desirable. The ionimplantation process, however, introduces difficulty in removing thephotoresist material during the subsequent photoresist strippingprocess. Specifically, during the ion implantation process, ionspenetrate into the outer regions of the photoresist material causingchemical bonds in the photoresist material outer regions to becomecross-linked. Thus, the cross-linked outer regions of the photoresistmaterial form a photoresist crust which is difficult to remove duringthe photoresist stripping process.

[0008]FIG. 1A is an illustration showing a cross-section of a patternedphotoresist layer previously used as an ion implantation mask, inaccordance with the prior art. During the ion implantation process, ions131 are implanted into target regions 129 of a substrate material 121,where the target regions 129 are not protected by the photoresistmaterial. Ions 131 entering the photoresist material cause the chemicalbonds in the photoresist material to become cross-linked. Since the ions131 only penetrate a limited distance through the photoresist material,the cross-linked photoresist is found near the outer portions of thephotoresist material. The cross-linked photoresist is commonly calledphotoresist crust. The photoresist crust is typically characterized by atop photoresist crust 125 and a side photoresist crust 127. Thethickness of the photoresist crust is generally dependent on the dosageof implant species and the ion implant energy in the photoresistmaterial. Since the ions generally bombard the photoresist material in adownward direction, the top photoresist crust 125 is generally thickerthan the side photoresist crust 127. The unaffected photoresist materialunderneath the photoresist crust is referred to as a bulk photoresistmaterial 123.

[0009] Generally, the stripping process for photoresist materials usedin wafer fabrication processes other than ion implantation involvesheating the photoresist material to a sufficiently high temperature tocause the photoresist material to be removed through volatilization.This high temperature photoresist stripping process is commonly calledashing. Ashing, however, is not appropriate for stripping photoresistmaterial that has been used as an ion implantation mask. Specifically,the photoresist crust is resistant to the ashing process. As thetemperature increases, the pressure of the volatile bulk photoresistportion underneath the photoresist crust increases. Eventually, at highenough temperature, the bulk photoresist portion will “pop” through thephotoresist crust. Such “popping” causes fragments of the photoresistcrust to be spread over the wafer and the chamber. The photoresist crustfragments adhere tenaciously to the wafer. Thus, removal of thephotoresist crust fragments from the wafer can be difficult if notimpossible. Furthermore, the ion implantation process often useselements such as arsenic which can present a serious hazard whencontained in photoresist crust fragments being cleaned from the chamber.Therefore, removal of the photoresist crust is generally performed at alow enough temperature to prevent popping.

[0010]FIG. 1B is an illustration showing the problem wherein the bulkphotoresist portion pops through the top photoresist crust, inaccordance with the prior art. The bulk photoresist portion 123 is shownpopping through the top photoresist crust 125 at a location 141. Theresulting top photoresist fragments 143 are shown adhering to thesubstrate material 121.

[0011] Stripping of the photoresist crust at low temperature istypically performed by exposing the photoresist crust to radicals formedfrom various processing gases such as O₂:N₂H₂, O₂:N₂:CF₄, NH₃, O₂,O₂:CF₄, and O₂:Cl₂, where “:” denotes a gas mixture. The radicals serveto break the cross-linked chemical bonds of the photoresist crust, thusallowing the photoresist crust to be removed. Photoresist strippingusing these processing gases at low temperature typically requires anextended amount of time, thus reducing wafer throughput. Also, handlingsome of these processing gases such as N₂H₂, NH₃, and Cl₂ generallyinvolves special requirements and safety features which can increase thecapital cost of the wafer processing equipment. Furthermore, photoresiststripping using these processing gases commonly results in a problemwherein the side photoresist crust is removed before the top photoresistcrust, thus allowing the bulk photoresist portion to be removed fromunderneath the top photoresist crust. This problem is commonly called“bulk photoresist undercut”.

[0012]FIG. 1C is an illustration showing the undercut problem whereinthe side photoresist crust is removed allowing the bulk photoresist tobe undercut, in accordance with the prior art. The side photoresistcrust (not shown) is removed prior to the top photoresist crust 127.Removal of the side photoresist crust causes the bulk photoresistportion 123 to be exposed to the radicals. Exposure of the bulkphotoresist portion 123 to the radicals along with the volatile natureof the bulk photoresist portion 123 causes an undercut 151 region to becreated. The undercut region 151 leaves the top photoresist crust 127susceptible to breaking off or falling onto the substrate material 121.If allowed to contact the substrate material 121, the top photoresistcrust 127 will adhere tenaciously causing its removal to be difficult ifnot impossible.

[0013] In view of the foregoing, there is a need for a method and anapparatus for stripping photoresist material that has been used as anion implantation mask. Specifically, the method and apparatus shouldavoid the problems of the prior art by using a processing gas that canmore efficiently and economically strip the photoresist material whilepreventing popping and undercut of the bulk photoresist.

SUMMARY OF THE INVENTION

[0014] Broadly speaking, the present invention fills these needs byproviding an apparatus and method for using H₂O vapor as a processinggas for stripping photoresist material from a substrate having apatterned photoresist layer previously used as an ion implantation mask.The patterned photoresist layer is characterized by a photoresist crustcovering a bulk photoresist portion. It should be appreciated that thepresent invention can be implemented in numerous ways, including as aprocess, an apparatus, a system, a device, or a method. Severalembodiments of the present invention are described below.

[0015] In one embodiment, a method for stripping photoresist materialfrom a substrate in a chamber is disclosed. The method includesproviding a substrate having a patterned photoresist layer that haspreviously been used as an ion implantation mask. The previous use ofthe patterned photoresist layer in an ion implantation process formed aphotoresist crust on an outer surface of the patterned photoresistlayer. Thus, the patterned photoresist layer is defined by a bulkphotoresist portion and the photoresist crust. In accordance with themethod, the substrate is placed in the chamber and heated in thechamber. The method further includes providing H₂O vapor to betransformed into a reactive form of H and a reactive form of O. Thereactive forms of H and O react with the photoresist crust to remove thephotoresist crust from the bulk photoresist portion of the patternedphotoresist layer.

[0016] In another embodiment, a method for stripping photoresistmaterial from a substrate in a chamber is disclosed. The substrate has apatterned photoresist layer that has been previously used as an ionimplantation mask such that a photoresist crust is formed on an outersurface of the patterned photoresist layer. Thus, the patternedphotoresist layer is defined by a bulk photoresist portion and thephotoresist crust. The substrate is placed on a chuck in the chamber.The method includes providing H₂O vapor to an applicator tube andapplying microwave power to the H₂O vapor in the applicator tube. TheH₂O vapor is transformed into H radicals and O radicals. The methodfurther includes flowing the H radicals and the O radicals from theapplicator tube to the substrate. Upon reaching the substrate, the Hradicals and the O radicals react with the photoresist crust to removethe photoresist crust from the bulk photoresist portion of the patternedphotoresist layer.

[0017] In another embodiment, a method for stripping photoresistmaterial from a substrate in a chamber is disclosed. The substrate has apatterned photoresist layer that has been previously used as an ionimplantation mask such that a photoresist crust is formed on an outersurface of the patterned photoresist layer. Thus, the patternedphotoresist layer is defined by a bulk photoresist portion and thephotoresist crust. The substrate is placed on a chuck in the chamber.The method includes providing H₂O vapor to the chamber. In accordancewith the method, radio frequency power is applied to the H₂O vapor inthe chamber to transform the H₂O vapor into a plasma containing H ions,H radicals, O ions, and O radicals. The method further includes applyinga bias voltage to the chuck to attract the H ions and the O ions to thesubstrate. Upon reaching the substrate, the H ions and the O ions reactwith the photoresist crust to remove the photoresist crust from the bulkphotoresist portion of the patterned photoresist layer.

[0018] In another embodiment, an apparatus for removing a patternedphotoresist layer from a semiconductor wafer is disclosed. The apparatusincludes a chamber having an internal region configured to contain aplasma. A semiconductor wafer support structure is disposed within thechamber internal region. The semiconductor wafer support structure isconfigured to hold a semiconductor wafer in exposure to the plasma. AnH₂O vapor supply line is configured to supply an H₂O vapor to a plasmageneration region. The apparatus further includes a power supply forgenerating the plasma in the plasma generation region. The plasmageneration region is configured to supply the plasma to the chamberinternal region.

[0019] In another embodiment, an apparatus for removing a patternedphotoresist layer from a semiconductor wafer is disclosed. The apparatusincludes a chamber having an internal region defined by a top, a bottom,and sides. A semiconductor wafer support structure is disposed in closeproximity to the bottom of the chamber internal region. Thesemiconductor wafer support structure is configured to hold asemiconductor wafer having a patterned photoresist layer. The apparatusalso includes an applicator tube in open communication with the top ofthe chamber internal region. An H₂O vapor supply line is configured tosupply H₂O vapor to the applicator tube. The apparatus further includesa power supply configured to apply microwave power to the applicatortube. The microwave power is used to transform the H₂O vapor into Hradicals and O radicals. The H radicals and the O radicals flow throughthe chamber internal region to reach the patterned photoresist layer ofthe semiconductor wafer. Upon reaching the patterned photoresist layerof the semiconductor wafer, the H radicals and the O radicals react toremove at least a portion of the patterned photoresist layer.

[0020] In another embodiment, an apparatus for removing a patternedphotoresist layer from a semiconductor wafer is disclosed. The apparatusincludes a chamber having an internal region defined by a top, a bottom,and sides. A semiconductor wafer support structure is disposed in closeproximity to the bottom of the chamber internal region. Thesemiconductor wafer support structure is configured to hold asemiconductor wafer having a patterned photoresist layer. The apparatusalso includes an electrically conductive coil disposed above the top ofthe chamber internal region. An H₂O vapor supply line is configured tosupply H₂O vapor to the chamber internal region. The apparatus includesa first power supply configured to supply radio frequency power to thecoil. The radio frequency power supplied to the coil is used to inducean electric current in the chamber internal region. The induced electriccurrent transforms the H₂O vapor into H ions, H radicals, O ions, and Oradicals. The apparatus further includes a second power supplyconfigured to supply radio frequency power to the semiconductor wafersupport structure. The radio frequency power supplied to thesemiconductor wafer support structure causes the semiconductor wafersupport structure to have a bias voltage. The bias voltage attracts theH ions and the O ions to the patterned photoresist layer of thesemiconductor wafer. Upon reaching the patterned photoresist layer ofthe semiconductor wafer, the H ions and the O ions react to remove atleast a portion of the patterned photoresist layer.

[0021] The advantages of the present invention are numerous. Mostnotably, the apparatus and method for using H₂O vapor as a processinggas as disclosed in the present invention avoids the problems of theprior art by effectively stripping the photoresist material having thephotoresist crust without causing the photoresist crust to pop or beundercut. Thus, the present invention eliminates the problems of theprior art by using H₂O vapor as a safe, effective, and economicalprocessing gas for stripping photoresist material having a photoresistcrust.

[0022] Other aspects and advantages of the invention will become moreapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, illustrating by way of example thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention, together with further advantages thereof, may bestbe understood by reference to the following description taken inconjunction with the accompanying drawings in which:

[0024]FIG. 1A is an illustration showing a cross-section of a patternedphotoresist layer previously used as an ion implantation mask, inaccordance with the prior art;

[0025]FIG. 1B is an illustration showing the problem wherein the bulkphotoresist portion pops through the top photoresist crust, inaccordance with the prior art;

[0026]FIG. 1C is an illustration showing the undercut problem whereinthe side photoresist crust is removed allowing the top photoresist crustto be undercut, in accordance with the prior art;

[0027]FIG. 2 is an illustration showing a downstream chamber, inaccordance with one embodiment of the present invention;

[0028]FIG. 3 is an illustration showing an exemplary cross-section of apatterned photoresist layer previously used as an ion implantation maskprior to the downstream chamber photoresist stripping experiments;

[0029]FIG. 4 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂:N₂H₂ as the processing gas inthe downstream chamber;

[0030]FIG. 5 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂:N₂:CF₄ as the processing gas inthe downstream chamber;

[0031]FIG. 6 is an illustration showing the photoresist stripping effectcorresponding to the experiment using NH₃ as the processing gas in thedownstream chamber;

[0032]FIG. 7 is an illustration showing the photoresist stripping effectcorresponding to the experiment using H₂O vapor as the processing gas inthe downstream chamber, in accordance with one embodiment of the presentinvention;

[0033]FIG. 8 is an illustration showing the etching chamber used toperform a biased photoresist stripping process, in accordance with oneembodiment of the present invention;

[0034]FIG. 9 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂ as the processing gas in theetching chamber;

[0035]FIG. 10 is an illustration showing the photoresist strippingeffect corresponding to the experiment using O₂:Cl₂ as the processinggas in the etching chamber;

[0036]FIG. 11 is an illustration showing the photoresist strippingeffect corresponding to the experiment using O₂:CF₄ as the processinggas in the etching chamber;

[0037]FIG. 12 is an illustration showing the photoresist strippingeffect corresponding to the experiment using H₂O vapor as the processinggas in the etching chamber, in accordance with one embodiment of thepresent invention;

[0038]FIG. 13 is an illustration showing a flowchart of the method forperforming a photoresist stripping process using H₂O vapor in thedownstream chamber, in accordance with one embodiment of the presentinvention; and

[0039]FIG. 14 is an illustration showing a flowchart of the method forperforming a biased photoresist stripping process using H₂O vapor in theetching chamber, in accordance with one embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] An invention is disclosed for methods and apparatuses for usingH₂O vapor as a processing gas for stripping photoresist materials from asubstrate having a patterned photoresist layer previously used as an ionimplantation mask. Use of the patterned photoresist layer as the ionimplantation mask causes the photoresist materials to form an outerphotoresist crust having cross-linked chemical bonds. The photoresistcrust covers a bulk photoresist portion having normal photoresistchemical bonds. Broadly speaking, the present invention provides forusing H₂O vapor to efficiently strip the photoresist crust withoutcausing the bulk photoresist portion to either pop through or beundercut from the photoresist crust. Thus, the present inventioneliminates the problems of the prior art by using H₂O vapor as a safe,efficient, and economical processing gas for stripping photoresistmaterials having photoresist crust.

[0041] In the following description, numerous specific details are setforth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known process operations havenot been described in detail in order not to unnecessarily obscure thepresent invention.

[0042] In a photolithography process to create an ion implantation mask,a photoresist material is first deposited onto a semiconductor wafer.The photoresist material is then exposed to light filtered by a reticle.The reticle is generally a glass plate that is patterned with exemplaryfeature geometries that block light from passing through the reticle.After passing through the reticle, the light contacts the surface of thephotoresist material. The light changes the chemical composition of theexposed photoresist material. With a positive photoresist material,exposure to the light renders the exposed photoresist material insolublein a developing solution. Conversely, with a negative photoresistmaterial, exposure to the light renders the exposed photoresist materialsoluble in the developing solution. After exposure to the light, thesoluble portion of the photoresist material is removed, leaving thepatterned photoresist layer. An ion implantation process is thenperformed on the semiconductor wafer having the patterned photoresistlayer. In general, the ion implantation process involves implanting ionsof elements (e.g., P, B, As, etc . . . ) into the semiconductor waferregions that are not protected by the patterned photoresist material.After the ion implantation process is completed, the patternedphotoresist material must be stripped (i.e., removed) from thesemiconductor wafer. Stripping of the patterned photoresist materialmust be performed thoroughly yet carefully to avoid damaging thesemiconductor wafer.

[0043] Ion implantation introduces difficulty in removing thephotoresist material during the post ion implant photoresist strippingprocess. Specifically, during the ion implantation process, ionspenetrate into the outer regions of the photoresist material causing thechemical bonds of the photoresist material to become cross-linked (i.e.,H—C—H becomes C—C—C). Thus, the cross-linked outer regions of thephotoresist material forms the photoresist crust which is difficult toremove during the photoresist stripping process. The present inventionprovides methods and apparatuses by which H₂O vapor can be used to stripthe crust and corresponding bulk portion of the photoresist materialused as the ion implantation mask.

[0044]FIG. 2 is an illustration showing a downstream photoresiststripping chamber (“downstream chamber”) 200, in accordance with oneembodiment of the present invention. The downstream chamber 200 is anapparatus that can be used to perform the post ion implant photoresiststripping process. A chamber internal region 208 is defined by chamberwalls 202, a chamber bottom 204, and a chamber top 206. A semiconductorwafer support structure (or “chuck”) 217 is positioned within thechamber internal region 208 near the chamber bottom 204. The chuck 217contains a number of lifting pins 219 that are used to raise and lower asemiconductor wafer (or “wafer”) 221 placed on the chuck 217 forprocessing. The chuck 217 also includes a heater 223 configured tooperate using electric power. The downstream chamber 200 is furtherdefined by an applicator tube 203 positioned above the chamber top 206.The applicator tube 203 is configured to be in open communication withthe chamber internal region 208 via a shower head 209. A processing gassupply line 201 is in fluid communication with the applicator tube 203to supply a processing gas. In the present invention, the preferredprocessing gas is either H₂O vapor alone or H₂O vapor in gas mixture.However, the processing gas supply line 201 can be configured to supplyvirtually any type of processing gas. A microwave power supply 205 isalso connected to the applicator tube 203 to supply microwave power tothe processing gas within the applicator tube 203. The microwave powertransforms the processing gas into radicals 215 of its constituentelements. In the present invention, the radicals 215 include primarily Hradicals and O radicals. The radicals 215 flow through the shower head209 into the chamber internal region 208 toward the wafer 221. Theradicals isotropically (i.e., uniformly in direction) contact the wafer221 and react to remove materials present on the wafer 221 surface.

[0045] In a preferred embodiment of the present invention, H₂O vapor isused as the processing gas in the downstream chamber 200 to strip thephotoresist crust. In the preferred embodiment, a partial vacuumpressure of about 1 torr is provided in the chamber internal region 208.In alternate embodiments, the partial vacuum pressure can be providedwithin a range extending from about 0.5 torr to about 5 torr. Also inthe preferred embodiment, H₂O vapor is supplied to the applicator tube203 at a flow rate of about 2000 standard cm³ per second (std. cc/sec).In alternate embodiments, the H₂O vapor can be supplied at a flow ratewithin a range extending from about 100 std. cc/sec to about 4000 std.cc/sec, but more preferably within a range extending from about 500 std.cc/sec to about 3000 std. cc/sec. The preferred embodiment furtherincludes applying a microwave power of about 3 kW from the microwavepower supply 205 to the H₂O vapor in the applicator tube 203. Inalternate embodiments, the microwave power can be applied within a rangeextending from about 0.5 kW to about 5 kW, but more preferably within arange extending from about 1 kW to about 4 kW. In the preferredembodiment, the chuck 217 is heated by the heater 223 to maintain thewafer 221 temperature at about 100° C. In alternate embodiments, thewafer temperature can be maintained within a range extending from about25° C. to about 130° C., but more preferably within a range extendingfrom about 70° C. to about 110° C. The photoresist crust stripping rateincreases with higher wafer 221 temperatures. However, it is necessaryto maintain the wafer 221 temperature below about 130° C. to prevent thebulk photoresist portion from popping through the photoresist crust. Thewafer 221 lifting pins 219 can be either up or down during thephotoresist stripping process. However, since the wafer 221 temperatureis primarily controlled by heat transfer from the chuck 217, it ispreferable to have the lifting pins 219 down during the photoresiststripping process, thus placing the wafer 221 in closer proximity to thechuck 217.

[0046] The usefulness of the present invention is demonstrated through aseries of experiments. In the series of experiments, the post ionimplant photoresist stripping effectiveness of a number of differentprocessing gas chemistries are tested in the downstream chamber 200. Theprinciple experimental parameters include processing gas chemistry,chamber internal region 208 pressure, microwave power, processing gasflow rate, wafer 221 temperature, and stripping process duration. Table1 shows a summary of the principle experimental parameters for each ofthe tested processing gas chemistries. The experimental results arecharacterized in terms of photoresist crust strip rate (“crust striprate”) and bulk photoresist portion strip rate (“bulk strip rate”).Also, the ratio of the crust strip rate to the bulk strip rate iscalculated to provide a measure of how much the bulk photoresist isbeing preferentially stripped. The ratio of the crust strip rate to thebulk strip rate is referred to as “crust selectivity.” It is mostdesirable to have the photoresist crust and the bulk photoresist stripat equal rates (i.e., crust selectivity equal to one) to minimize bulkphotoresist undercut. However, the cross-linked nature of thephotoresist crust generally causes the crust selectivity to be much lessthan one. Nevertheless, it is necessary to have an acceptably high crustselectivity to prevent the undercut problem associated with the priorart. Table 2 shows a summary of the downstream chamber 200 experimentalresults corresponding to the principle experimental parameters presentedin Table 1.

[0047]FIG. 3 is an illustration showing an exemplary cross-section 300of a patterned photoresist layer previously used as an ion implantationmask prior to the downstream chamber 200 photoresist strippingexperiments described in Table 1. The exemplary cross-section 300includes the photoresist material disposed between ion implantationtarget regions containing implanted ions 302. The photoresist materialis defined by a top photoresist crust 301, side photoresist crusts 303,and a bulk photoresist portion 305. The top photoresist crust 301 isthicker than the side photoresist crusts 303. The entire patternedphotoresist layer is disposed on top of a substrate material 307. Thesubstrate material 307 can be composed of many types of materialsdepending on the design features present at the top surface of the wafer221. The photoresist stripping process is generally not affected by thetype of substrate material 307. However, the photoresist strippingprocess should be carefully performed to avoid stripping or damaging thesubstrate material 307. TABLE 1 Summary of Principle Parameters for theDownstream Stripping Chamber Experiments Chamber Micro- ProcessingStripping Processing Internal wave Gas Flow Wafer Process Gas PressurePower Rate Temperature Duration Chemistry (torr) (kW) (std. cc/sec) (°C.) (sec) O₂:N₂H₂ 1 3 4500 O₂ 100 120  500 N₂H₂ O₂:N₂:CF₄ 1 3 4500 O₂120 120  500 N₂  10 CF₄ NH₃ 1 3 1000 NH₃ 100 120 H₂O 1 3 2000 H₂O 80 120

[0048] TABLE 2 Summary of Results for the Downstream Stripping inChamber Experiments Processing Photoresist Crust Strip Bulk Strip GasProfile Description Rate Rate Crust Chemistry After Stripping (Å/min.)(Å/min.) Selectivity O₂:N₂H₂ Top crust remaining; 250 3000 0.08 Sidecrust gone; Bulk photoresist undercut O₂:N₂:CF₄ Top crust remaining; 30016000 0.02 Side crust gone; Bulk photoresist severely undercut NH₃ Topcrust thinned; 563 1850 0.30 Side crust gone; Very little bulkphotoresist undercut H₂O Top crust gone; 750 3750 0.20 Side crust gone;No sign of bulk photoresist undercut

[0049] As shown in Table 1, a downstream chamber 200 experiment isperformed using an O₂:N₂H₂ processing gas mixture. Specifically, theprocessing gas mixture is composed of O₂ and N₂H₂ mixed in a 9-to-1ratio, respectively, wherein the N₂H₂ contains 4% by weight H₂. Use ofthe O₂:N₂H₂ processing gas mixture for performing a low temperaturephotoresist stripping process is commonly known to those skilled in theart. One problem associated with the O₂:N₂H₂ processing gas is that ittakes an unacceptably long time (e.g., about 4 to 5 minutes) tocompletely strip a typical photoresist crust thickness. Table 1 showsthat of the four processing gas chemistries tested, O₂:N₂H₂ has thelowest crust strip rate at 250 Å/min. Also, the O₂:N₂H₂ processing gashas an unacceptably low crust selectivity of 0.08.

[0050]FIG. 4 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂:N₂H₂ as the processing gas inthe downstream chamber 200. A cross-section 308 of the post ion implantphotoresist material is shown after the O₂:N₂H₂ processing gasexperiment. The cross-section 308 shows a remaining top photoresistcrust 309 above a partially removed bulk photoresist portion 310. Theside photoresist crust 303 (see FIG. 3) is completely removed during theexperiment to expose the bulk photoresist portion 310 to the O₂:N₂H₂processing gas radicals. The unacceptably low crust selectivity of 0.08of the O₂:N₂H₂ processing gas causes significant undercut regions 311.The undercut regions 311 are undesirable because they leave theremaining top photoresist crust 309 susceptible to breaking off orfalling onto the substrate material 307. If allowed to contact thesubstrate material 307, the remaining top photoresist crust 309 willadhere tenaciously to the substrate material 307 and create difficultiesin completing the photoresist material stripping process.

[0051] As shown in Table 1, a downstream chamber 200 experiment isperformed using an O₂:N₂:CF₄ processing gas mixture. Specifically, theprocessing gas mixture is composed of O₂ and N₂ mixed in a 9-to-1 ratio,respectively, with about 2000 parts per million by mass (ppm) CF₄ added.CF₄ is commonly used to remove tough residues and polymers. Theexperiment shows that a small amount of CF₄ greatly increases the bulkstrip rate, but provides very little improvement with respect to thecrust strip rate. Thus, the problem associated with the O₂:N₂H₂processing gas of requiring an unacceptably long time to completelystrip a typical photoresist crust thickness also applies to theO₂:N₂:CF₄ processing gas. Furthermore, the O₂:N₂:CF₄ processing gas bulkstrip rate of 16000 Å/min results in a very low crust selectivity of0.02.

[0052]FIG. 5 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂:N₂:CF₄ as the processing gas inthe downstream chamber 200. A cross-section 314 of the post ion implantphotoresist material is shown after the O₂:N₂:CF₄ processing gasexperiment. The cross-section 314 shows a remaining top photoresistcrust 315 above a partially removed bulk photoresist portion 319. Theside photoresist crust 303 (see FIG. 3) is completely removed during theexperiment to expose the bulk photoresist portion 319 to the O₂:N₂:CF₄processing gas radicals. The extremely low crust selectivity of 0.02 ofthe O₂:N₂:CF₄ processing gas causes severe undercut regions 317. Theundercut regions 317 are more pronounced than the analogous undercutregions 311 in the O₂:N₂H₂ processing gas experiment. As with theO₂:N₂H₂ experiment, the undercut regions 317 are undesirable becausethey leave the remaining top photoresist crust 315 susceptible tobreaking off or falling onto the substrate material 307.

[0053] As shown in Table 1, a downstream chamber 200 experiment isperformed using NH₃ (i.e., ammonia) as the processing gas. The NH₃processing gas is used as a hydrogen source gas. The experiment showsthat the NH₃ processing gas has a higher crust strip rate (563 Å/min)than either the O₂:N₂H₂ or the O₂:N₂:CF₄ processing gases. The NH₃processing gas is also shown to have an acceptable crust selectivity of0.3. Unfortunately, NH₃ is toxic and requires appropriate handlingprecautions.

[0054]FIG. 6 is an illustration showing the photoresist stripping effectcorresponding to the experiment using NH₃ as the processing gas in thedownstream chamber 200. A cross-section 322 of the post ion implantphotoresist material is shown after the NH₃ processing gas experiment.The cross-section 322 shows a remaining top photoresist crust 323 abovea remaining bulk photoresist portion 327. The remaining top photoresistcrust 323 is noticeably thinned by the NH₃ processing gas experiment.Also, the side photoresist crust 303 (see FIG. 3) is completely removedduring the experiment to expose the bulk photoresist portion 327 to theradicals. However, the remaining bulk photoresist portion 327 indicatesonly a slight undercut 325. The relatively small amount of undercut 325is expected due to the acceptable crust selectivity of 0.3.

[0055] As shown in Table 1, a downstream chamber 200 experiment isperformed using an H₂O vapor as the processing gas. The H₂O vapor isused as a hydrogen source gas. The experiment shows that of the fourprocessing gases tested, H₂O vapor provides the highest crust strip rateat 750 Å/min. The H₂O vapor is also shown to have an acceptable crustselectivity of 0.2. Additionally, H₂O vapor has the advantages of beingnon-toxic, safe (e.g., non-flammable), readily available, andinexpensive.

[0056]FIG. 7 is an illustration showing the photoresist stripping effectcorresponding to the experiment using H₂O vapor as the processing gas inthe downstream chamber 200, in accordance with one embodiment of thepresent invention. A cross-section 331 of the post ion implantphotoresist material is shown after the H₂O vapor processing gasexperiment. The cross-section 331 shows only a remaining bulkphotoresist portion 333. Both the top photoresist crust 301 (see FIG. 3)and the side photoresist crust 303 (see FIG. 3) are completely removedduring the experiment to expose the bulk photoresist portion 333 to theradicals. Due to the fast crust strip rate of 750 Å/min and theacceptable crust selectivity of 0.2, the bulk photoresist portion 333does not show any indication of undercut.

[0057] The downstream chamber 200 experiments clearly demonstrate theusefulness of H₂O vapor as a processing gas for stripping post ionimplant photoresist material. However, it may be beneficial in somecircumstances to have an even higher crust strip rate. As an alternativeto the isotropic photoresist stripping technique implemented with thedownstream chamber 200, a directionally biased stripping technique(“biased stripping”) can be implemented with an inductively coupledplasma etching chamber (“etching chamber”) 400. The biased strippingpreferentially directs the ions to move in a direction substantiallyperpendicular to an upper surface of a chuck having a bias voltage.Therefore, the biased stripping causes the ions to contact the wafer topsurface in a substantially perpendicular manner such that thephotoresist top crust is preferentially stripped. The biased strippingshould be performed carefully, however, to prevent undesirable etchingof a substrate material which could cause defects in the integratedcircuitry being fabricated on the wafer.

[0058]FIG. 8 is an illustration showing the etching chamber 400 used toperform a biased photoresist stripping process, in accordance with oneembodiment of the present invention. A chamber internal region 402 indefined by chamber walls 401, a chamber top 404, and a chamber bottom406. The chamber top 404 is configured to have an opening to the chamberinternal region 402. The opening in the chamber top 404 is covered by awindow 403. A semiconductor wafer support structure (or “chuck”) 405 ispositioned within the chamber internal region 402 near the chamberbottom 406. The chuck 405 contains a number of lifting pins (not shown)that are used to raise and lower a semiconductor wafer (or “wafer”) 407placed on the chuck 405 for processing. The chuck 405 is furtherconfigured to receive a flow of fluid for controlling the temperature ofthe chuck 405. A processing gas supply line 415 is in fluidcommunication with the chamber internal region 402 to supply aprocessing gas. An electrically conductive coil 419 is configured abovethe window 403. A radio frequency power supply 421 is configured tosupply radio frequency power to the coil 419. In general, the radiofrequency power supply 421 is electrically connected to matchingcircuitry 423 through a connection 437. The matching circuitry 423 is infurther electrical communication with the coil 419 through a connection435. The radio frequency power supplied to the coil 419 is used togenerate an electromagnetic field about the coil 419. Theelectromagnetic field induces an electric current within the chamberinternal region 402. The induced electric current is used to transformthe processing gas into a plasma 425 containing ions and radicals of itsconstituent elements. The chuck 405 is configured to receive a biasvoltage. In general, a radio frequency power supply 427 is electricallyconnected to matching circuitry 429 through a connection 433. Thematching circuitry 429 is in further electrical communication with thechuck 405 through a connection 431. In this manner, the radio frequencypower supply 427 is used to provide the chuck 405 with the bias voltage.The bias voltage creates a voltage potential that is used to attract theplasma 425 ions to the wafer 407. The ions directionally (i.e., biasedin direction toward the wafer 407 top surface) contact the wafer 407 andreact to remove photoresist materials present on the wafer 407 surface.Also, the plasma 425 radicals isotropically (i.e., uniformly indirection) contact the wafer 407 and react to remove photoresistmaterials present on the wafer 407 surface.

[0059] In a preferred embodiment of the present invention, H₂O vapor isused as the processing gas in the etching chamber 400 to strip thephotoresist crust. In the preferred embodiment, a partial vacuumpressure of about 0.2 torr is provided in the chamber internal region402. In alternate embodiments, the partial vacuum pressure can beprovided within a range extending from about 0.001 torr to about 1 torr,but more preferably within a range extending from about 0.07 torr toabout 0.5 torr. Also in the preferred embodiment, H₂O vapor is suppliedto the chamber internal region 402 at a flow rate of about 2000 std.cc/sec. In alternate embodiments, the H₂O vapor can be supplied at aflow rate within a range extending from about 100 std. cc/sec to about4000 std. cc/sec, but more preferably within a range extending fromabout 500 std. cc/sec to about 3000 std. cc/sec. The preferredembodiment further includes applying a radio frequency power of about2.5 kW from the radio frequency power supply 421 to the coil 419 toinduce the electric current in the chamber internal region 402 whichwill generate the plasma 425. In alternate embodiments, the radiofrequency power can be applied within a range extending from about 0.5kW to about 3 kW, but more preferably within a range extending fromabout 1.5 kW to about 3 kW. In the preferred embodiment, the chuck 405temperature is controlled to maintain the wafer 407 temperature at about70° C. In alternate embodiments, the wafer temperature can be maintainedwithin a range extending from about 25° C. to about 130° C., but morepreferably within a range extending from about 25° C. to about 100° C.The photoresist crust stripping rate increases with higher wafer 407temperatures. However, it is necessary to maintain the wafer 407temperature below about 130° C. to prevent the bulk photoresist portionfrom popping through the photoresist crust. The wafer 407 lifting pinscontained within the chuck 405 can be either up or down during thebiased photoresist stripping process. However, since the wafer 407temperature is primarily controlled by heat transfer from the chuck 405,it is preferable to have the lifting pins down during the biasedphotoresist stripping process, thus placing the wafer 407 in closerproximity to the chuck 405. The preferred embodiment further includesapplying a radio frequency power of about 250 W from the radio frequencypower supply 427 to the chuck 405. The radio frequency power providesthe chuck 405 with a bias voltage creating a voltage potential thatcauses the ions to be attracted toward the chuck 405 and wafer 407. Inalternate embodiments, the radio frequency power can be applied within arange extending from about 0 W to about 800 W, but more preferablywithin a range extending from about 0 W to about 600 W.

[0060] The usefulness of the present invention is demonstrated through aseries of experiments. In the series of experiments, the post ionimplant photoresist stripping effectiveness of a number of differentprocessing gas chemistries are tested in the etching chamber 400. Theprinciple experimental parameters include processing gas chemistry,chamber internal region 402 pressure, radio frequency power applied tothe coil 419 (“coil power”), radio frequency power applied to the chuck405 (“chuck power”), processing gas flow rate, wafer 407 temperature,and stripping process duration. Table 3 shows a summary of the principleexperimental parameters for each of the tested processing gaschemistries. The experimental results are characterized in terms ofphotoresist crust strip rate (“crust strip rate”) and rate of substrateloss due to etching (“substrate etch rate”). Table 4 shows a summary ofthe etching chamber 400 experimental results corresponding to theprinciple experimental parameters presented in Table 3. TABLE 3 Summaryof Principle Parameters for the Etching Chamber Experiments Cham-Processing ber Coil Gas Flow Wafer Stripping Processing Internal Pow-Chuck Rate Tem- Process Gas Pressure er Power (std. cc/ peratureDuration Chemistry (torr) (W) (W) sec) (C.) (sec) O₂ 0.09 750 250 200 O₂60 40 O₂:Cl₂ 0.09 750 100 200 O₂ 75 240 100 Cl₂ O₂:CF₄ 0.09 750 100 200O₂ 75 110  5 CF₄ H₂O 0.09 750 250 900 H₂O 60 40

[0061] TABLE 4 Summary of Results for the Etching Chamber ExperimentsProcessing Crust Strip Substrate Gas Photoresist Profile Rate Etch RateChemistry Description After Stripping (Å/min) (Å/min) O₂ Top crust gone;2250  0 Side crust remaining; No noticeable substrate loss O₂:Cl₂ Topcrust gone; 530 not available Side crust gone; No noticeable substrateloss O₂:CF₄ Top crust gone; 1500 150 Side crust gone; Very noticeablesubstrate loss H₂O Top crust gone; 3000  8 Side crust remaining; Verylittle substrate loss

[0062] As shown in Table 3, an etching chamber 400 experiment isperformed using O₂ as the processing gas. The O₂ processing gas providesa crust strip rate of 2250 Å/min. Also, use of the O₂ processing gasdoes not cause etching of the substrate material.

[0063]FIG. 9 is an illustration showing the photoresist stripping effectcorresponding to the experiment using O₂ as the processing gas in theetching chamber 400. A cross-section 508 of the post ion implantphotoresist material is shown after the O₂ processing gas experiment.The cross-section 508 shows the top photoresist crust 301 (see FIG. 3)removed from a remaining bulk photoresist portion 513. The remainingbulk photoresist portion 513 is bordered by remaining side photoresistcrust sections 511 having approximately the same height as the remainingbulk photoresist portion 513.

[0064] As shown in Table 3, an etching chamber 400 experiment isperformed using an O₂:Cl₂ processing gas mixture. Specifically, theprocessing gas mixture is composed of O₂ and Cl₂ mixed in a 2-to-1ratio, respectively. One problem associated with the 0 _(2:Cl) ₂processing gas is that it takes an unacceptably long time to completelystrip a typical photoresist crust thickness. Table 3 shows that of thefour processing gas chemistries tested, O_(2:Cl) ₂ has the lowest cruststrip rate at 530 Å/min.

[0065]FIG. 10 is an illustration showing the photoresist strippingeffect corresponding to the experiment using O₂:Cl₂ as the processinggas in the etching chamber 400. A cross-section 516 of the post ionimplant photoresist material is shown after the O₂:Cl₂ processing gasexperiment. The cross-section 516 shows the top photoresist crust 301(see FIG. 3) and the side photoresist crust 303 (see FIG. 3) removedfrom a remaining bulk photoresist portion 521.

[0066] As shown in Table 3, an etching chamber 400 experiment isperformed using an O₂:CF₄ processing gas mixture. Specifically, theprocessing gas mixture is composed of O₂ and CF₄ mixed in a 40-to-1ratio, respectively. Use of the O₂:CF₄ processing gas provides a cruststrip rate of 1500 Å/min. However, use of the relatively small amount ofCF₄ in the O₂:CF₄ processing gas results in an unacceptable substrateetch rate of 150 Å/min.

[0067]FIG. 11 is an illustration showing the photoresist strippingeffect corresponding to the experiment using O₂:CF₄ as the processinggas in the etching chamber 400. A cross-section 524 of the post ionimplant photoresist material is shown after the O₂:CF₄ processing gasexperiment. The cross-section 524 shows the top photoresist crust 301(see FIG. 3) and the side photoresist crust 303 (see FIG. 3) removedfrom a remaining bulk photoresist portion 529. Additionally, thesubstrate material 307 is shown to be unacceptably etched as indicatedby areas 533.

[0068] As shown in Table 3, an etching chamber 400 experiment isperformed using an H₂O vapor as the processing gas. The H₂O vapor isused as a hydrogen source gas. The experiment shows that of the fourprocessing gases tested, H₂O vapor provides the highest crust strip rateat 3000 Å/min. The H₂O vapor is also shown to have an acceptably lowsubstrate etch rate of 8 Å/min. In the preferred embodiment of thepresent invention, there is essentially no etching of the substratematerial. Additionally, H₂O vapor has the advantages of being non-toxic,safe (e g., non-flammable), readily available, and inexpensive.

[0069]FIG. 12 is an illustration showing the photoresist strippingeffect corresponding to the experiment using H₂O vapor as the processinggas in the etching chamber 400, in accordance with one embodiment of thepresent invention. A cross-section 534 of the post ion implantphotoresist material is shown after the H₂O vapor processing gasexperiment. The cross-section 534 shows the top photoresist crust 301(see FIG. 3) removed from a remaining bulk photoresist portion 539. Theremaining bulk photoresist portion 539 is bordered by remaining sidephotoresist crust sections 537 having approximately the same height asthe remaining bulk photoresist portion 539.

[0070] The etching chamber 400 experiments clearly demonstrate theusefulness of H₂O vapor as a processing gas for accelerated stripping ofpost ion implant photoresist material. Thus, use of H₂O vapor as theprocessing gas in both the downstream chamber 200 and the etchingchamber 400 provides for efficient photoresist crust stripping withoutthe popping and undercut problems of the prior art. The H₂O vapor isalso effective for stripping photoresist material in both the downstreamchamber 200 and the etching chamber 400 when combined with otherprocessing gases such as O₂ or N₂.

[0071]FIG. 13 is an illustration showing a flowchart of the method forperforming a photoresist stripping process using H₂O vapor in thedownstream chamber 200, in accordance with one embodiment of the presentinvention. The method begins with a step 601 wherein the wafer 221 isplaced on the chuck 217 in the downstream chamber 200. In a step 603,the downstream chamber 200 is sealed. A step 605 requires the necessarypartial vacuum pressure to be obtained within the downstream chamber200. A step 607 requires the chuck 217 to be heated to obtain theappropriate wafer 221 temperature for the photoresist crust strippingprocess. In a step 609, the appropriate flow rate of H₂O vapor issupplied as the processing gas to the applicator tube 203. A step 611follows in which the required microwave power is supplied from themicrowave power supply 205 to the H₂O vapor processing gas in theapplicator tube 203. The microwave power causes the H₂O vapor to betransformed into H radicals and O radicals. In a step 613, the Hradicals and O radicals flow to the wafer 221 surface. The H radicalsand O radicals contact the wafer 221 surface in an isotropic manner toreact with the photoresist materials on the wafer 221 surface. The Hradicals and the O radicals are allowed to react with the photoresistmaterials on the wafer 221 surface until the photoresist crust isremoved. After removal of the photoresist crust, the remaining bulkphotoresist portion can be removed by either an Option A 614 or anOption B 622. Option A 614 includes a step 615 in which the temperatureof the chuck 217 is increased substantially. Under Option A 614, a step617 follows in which the H radicals and the O radicals are allowed tocontinue to react with the remaining bulk photoresist material while theincreased temperature assists in removing the remaining bulk photoresistmaterial through volatilization. Option B 622 begins with a step 619 inwhich the downstream chamber 200 is reset to its initial state prior tothe photoresist stripping process. Option B 622, then continues with astep 621 in which the wafer 221 is removed from the downstream chamber200. Under Option B 622, the method concludes with a step 623 in whichthe wafer 221 is transferred to a high temperature chamber where theremaining bulk photoresist material is exposed to high temperature(e.g., 200° C. to 300° C.). The high temperature removes the remainingbulk photoresist material through volatilization.

[0072]FIG. 14 is an illustration showing a flowchart of the method forperforming a biased photoresist stripping process using H₂O vapor in theetching chamber 400, in accordance with one embodiment of the presentinvention. The method begins with a step 701 in which the wafer 407 isplaced on the chuck 405 in the etching chamber 400. In a step 703, theetching chamber 400 is sealed. A step 705 requires the necessary partialvacuum pressure to be obtained within the etching chamber 400. A step707 requires the chuck 405 to be heated to obtain the appropriate wafer407 temperature for the photoresist crust stripping process. In a step709, the appropriate flow rate of H₂O vapor is supplied as theprocessing gas to the chamber internal region 402. A step 711 follows inwhich the required radio frequency power is applied from the radiofrequency power supply 421 to the coil 419. The radio frequency powercauses the coil 419 to induce an electric current in the chamberinternal region 402. The electric current in the chamber internal region402 causes the H₂O vapor processing gas to be transformed into H ions, Hradicals, O ions, and O radicals. In a step 713, radio frequency poweris applied from the radio frequency power supply 427 to the chuck 405 toprovide bias voltage to the chuck 405. The voltage potential created bythe bias voltage applied to the chuck 405 attracts the H ions and the Oions to the wafer 407. In a step 715, the H ions and the O ions areallowed to directionally (i.e., biased in direction toward the wafer 407top surface) contact the wafer 407 and react to remove the photoresistmaterial present on the wafer 407 surface. Also in step 715, the Hradicals and the O radicals are allowed to isotropically contact thewafer 407 and react to remove the photoresist material present on thewafer 407 surface. Due to the directionality of the H ions and the Oions, the photoresist material is preferentially removed in atop-to-bottom manner. After removal of the top photoresist crust, theremaining side photoresist crust and bulk photoresist portion can beremoved by either an Option A 717, an Option B 721, or an Option C 727.Option A 717 concludes the method with a step 719 in which the H ions,the H radicals, the O ions, and the O radicals are allowed to continueto react with the remaining side photoresist crust and bulk photoresistportion until the photoresist material is completely removed from thewafer 407. Option B 721 includes a step 723 in which the etching chamber400 is reset to its initial state prior to the photoresist strippingprocess. Under Option B 721, the method continues with a step 725 inwhich the wafer 407 is transferred from the etching chamber 400 to ahigh temperature chamber. Option B 721 concludes with a step 726 inwhich the high temperature chamber is used to remove the remainingphotoresist materials through volatilization. Option C 727 includes astep 729 in which the etching chamber 400 is reset to its initial stateprior to the photoresist stripping process. Under Option C 727, themethod continues with a step 731 in which the wafer 407 is transferredfrom the etching chamber 400 to the downstream chamber 200. Option C 727concludes with a step 733 in which the remaining photoresist materialsare removed using the downstream chamber 200.

[0073] While this invention has been described in terms of severalembodiments, it will be appreciated that those skilled in the art uponreading the preceding specifications and studying the drawings willrealize various alterations, additions, permutations and equivalentsthereof. It is therefore intended that the present invention includesall such alterations, additions, permutations, and equivalents as fallwithin the true spirit and scope of the invention.

What is claimed is:
 1. A method for stripping photoresist material froma substrate in a chamber, comprising: providing a substrate having apatterned photoresist layer, the patterned photoresist layer beingpreviously used as an ion implantation mask such that a photoresistcrust is formed on an outer surface of the patterned photoresist layer,the patterned photoresist layer thus being defined by a bulk photoresistportion and the photoresist crust, the substrate being placed in thechamber; heating the substrate in the chamber; and providing H₂O vapor,the H₂O vapor being transformed into a reactive form of H and a reactiveform of O, wherein the reactive forms of H and O react with thephotoresist crust, the reaction with the photoresist crust acting toremove the photoresist crust from the bulk photoresist portion of thepatterned photoresist layer.
 2. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 1, whereinthe substrate is heated to a temperature within a range extending fromabout 25° C. to about 130° C.
 3. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 1, furthercomprising: generating a partial vacuum pressure within the chamber, thepartial vacuum pressure being within a range extending from about 0.001torr to about 5 torr.
 4. A method for stripping photoresist materialfrom a substrate in a chamber as recited in claim 1, wherein the H₂Ovapor is provided at a flow rate within a range extending from about 100standard cubic centimeters per second (std. cc/sec) to about 4000 std.cc/sec.
 5. A method for stripping photoresist material from a substratein a chamber as recited in claim 1, further comprising: using amicrowave source to transform the H₂O vapor into H radicals and Oradicals, the microwave source operating within a power range extendingfrom about 500 Watts to about 5000 Watts.
 6. A method for strippingphotoresist material from a substrate in a chamber as recited in claim1, further comprising: using a radio frequency source to transform theH₂O vapor into H ions, H radicals, O ions, and O radicals, the radiofrequency source operating within a power range extending from about 500Watts to about 3000 Watts.
 7. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 1, whereinthe H₂O vapor is provided as a component of a multiple gas mixture.
 8. Amethod for stripping photoresist material from a substrate in a chamberas recited in claim 1, wherein the H₂O vapor is provided to remove boththe photoresist crust and the bulk photoresist portion of the patternedphotoresist layer.
 9. A method for stripping photoresist material from asubstrate in a chamber as recited in claim 1, further comprising:detecting the removal of the photoresist crust; and increasing thetemperature of the substrate after removal of the photoresist crust, thetemperature being increased within a range extending from about 130° C.to about 300° C., the increased temperature being maintained duringremoval of the bulk photoresist portion of the patterned photoresistlayer.
 10. A method for stripping photoresist material from a substratein a chamber, the substrate having a patterned photoresist layer, thepatterned photoresist layer being previously used as an ion implantationmask such that a photoresist crust is formed on an outer surface of thepatterned photoresist layer, the patterned photoresist layer thus beingdefined by a bulk photoresist portion and the photoresist crust, thesubstrate being placed on a chuck in the chamber; the method comprising:providing H₂O vapor to an applicator tube; applying microwave power tothe H₂O vapor in the applicator tube, the H₂O vapor being transformedinto H radicals and O radicals; and flowing the H radicals and the Oradicals from the applicator tube to the substrate, wherein the Hradicals and the O radicals react with the photoresist crust, thereaction with the photoresist crust acting to remove the photoresistcrust from the bulk photoresist portion of the patterned photoresistlayer.
 11. A method for stripping photoresist material from a substratein a chamber as recited in claim 10, further comprising: heating thechuck to increase the temperature of the substrate within a rangeextending from about 25° C. to about 130° C.
 12. A method for strippingphotoresist material from a substrate in a chamber as recited in claim10, further comprising: detecting the removal of the photoresist crust;and heating the chuck to increase the temperature of the substrate afterremoval of the photoresist crust, the temperature being increased withina range extending from about 130° C. to about 300° C., the increasedtemperature being maintained during removal of the bulk photoresistportion of the patterned photoresist layer.
 13. A method for strippingphotoresist material from a substrate in a chamber as recited in claim10, further comprising: generating a partial vacuum pressure within thechamber, the partial vacuum pressure being within a range extending fromabout 0.5 torr to about 5 torr.
 14. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 10, whereinthe H₂O vapor is provided to the applicator tube at a flow rate within arange extending from about 100 standard cubic centimeters per second(std. cc/sec) to about 4000 std. cc/sec.
 15. A method for strippingphotoresist material from a substrate in a chamber as recited in claim10, wherein the microwave power is provided within a range extendingfrom about 500 Watts to about 5000 Watts.
 16. A method for strippingphotoresist material from a substrate in a chamber as recited in claim10, wherein the H₂O vapor is provided as a component of a multiple gasmixture.
 17. A method for stripping photoresist material from asubstrate in a chamber as recited in claim 10, wherein the H₂O vapor isprovided to remove both the photoresist crust and the bulk photoresistportion of the patterned photoresist layer.
 18. A method for strippingphotoresist material from a substrate in a chamber, the substrate havinga patterned photoresist layer, the patterned photoresist layer beingpreviously used as an ion implantation mask such that a photoresistcrust is formed on an outer surface of the patterned photoresist layer,the patterned photoresist layer thus being defined by a bulk photoresistportion and the photoresist crust, the substrate being placed on a chuckin the chamber; the method comprising: providing H₂O vapor to thechamber; applying radio frequency power to the H₂O vapor in the chamber,the H₂O vapor being transformed into a plasma containing H ions, Hradicals, O ions, and O radicals; and applying a bias voltage to thechuck to attract the H ions and O ions to the substrate, wherein the Hions and the O ions react with the photoresist crust, the reaction withthe photoresist crust acting to remove the photoresist crust from thebulk photoresist portion of the patterned photoresist layer.
 19. Amethod for stripping photoresist material from a substrate in a chamberas recited in claim 18, further comprising: heating the chuck toincrease the temperature of the substrate within a range extending fromabout 25° C. to about 130° C.
 20. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 18, furthercomprising: generating a partial vacuum pressure within the chamber, thepartial vacuum pressure being within a range extending from about 0.001torr to about 1 torr.
 21. A method for stripping photoresist materialfrom a substrate in a chamber as recited in claim 18, wherein the H₂Ovapor is provided to the applicator tube at a flow rate within a rangeextending from about 100 standard cubic centimeters per second (std.cc/sec) to about 4000 std. cc/sec.
 22. A method for strippingphotoresist material from a substrate in a chamber as recited in claim18, wherein the radio frequency power is provided within a rangeextending from about 500 Watts to about 3000 Watts.
 23. A method forstripping photoresist material from a substrate in a chamber as recitedin claim 18, wherein the bias voltage being applied to the chuck isapplied using radio frequency power within a range extending from about0 Watts to about 800 Watts.
 24. A method for stripping photoresistmaterial from a substrate in a chamber as recited in claim 18, whereinthe H₂O vapor is provided as a component of a multiple gas mixture. 25.A method for stripping photoresist material from a substrate in achamber as recited in claim 18, further comprising: detecting theremoval of the photoresist crust; and providing H₂O vapor to the chamberto remove the bulk photoresist portion of the patterned photoresistlayer.
 26. An apparatus for removing a patterned photoresist layer froma semiconductor wafer, comprising: a chamber having an internal regionconfigured to contain a plasma; a semiconductor wafer support structuredisposed within the chamber internal region, the semiconductor wafersupport structure configured to hold a semiconductor wafer in exposureto the plasma; an H₂O vapor supply line configured to supply an H₂Ovapor to a plasma generation region; and a power supply for generatingthe plasma in the plasma generation region, the plasma generation regionconfigured to supply the plasma to the chamber internal region.
 27. Anapparatus for removing a patterned photoresist layer from asemiconductor wafer as recited in claim 26, further comprising: a heaterconfigured to increase the temperature of the semiconductor wafersupport structure, the temperature increase of the semiconductor wafersupport structure increasing the temperature of the semiconductor wafer.28. An apparatus for removing a patterned photoresist layer from asemiconductor wafer as recited in claim 26, wherein the power supply isa microwave power supply configured to supply a microwave power within arange extending from about 500 Watts to about 5000 Watts.
 29. Anapparatus for removing a patterned photoresist layer from asemiconductor wafer as recited in claim 26, wherein the power supply isa radio frequency power supply configured to supply a radio frequencypower within a range extending from about 500 Watts to about 3000 Watts.30. An apparatus for removing a patterned photoresist layer from asemiconductor wafer as recited in claim 26, further comprising: a radiofrequency power supply being configured to supply a radio frequencypower to the semiconductor wafer support structure, the radio frequencypower being within a range extending from about 0 Watts to about 800Watts, the radio frequency power providing the semiconductor wafersupport structure with a bias voltage.
 31. An apparatus for removing apatterned photoresist layer from a semiconductor wafer, comprising: achamber having an internal region, the internal region being defined bya top, a bottom, and sides; a semiconductor wafer support structuredisposed in close proximity to the bottom of the chamber internalregion, the semiconductor wafer support structure configured to hold asemiconductor wafer having a patterned photoresist layer; an applicatortube in open communication with the top of the chamber internal region;an H₂O vapor supply line configured to supply H₂O vapor to theapplicator tube; and a power supply configured to apply microwave powerto the applicator tube, the microwave power being used to transform theH₂O vapor into H radicals and O radicals, the H radicals and the Oradicals flowing through the chamber internal region to reach thepatterned photoresist layer of the semiconductor wafer, wherein the Hradicals and the O radicals react to remove at least a portion of thepatterned photoresist layer.
 32. An apparatus for removing a patternedphotoresist layer from a semiconductor wafer as recited in claim 31,further comprising: a heater configured to increase the temperature ofthe semiconductor wafer support structure within a temperature rangefrom about 25° C. to about 300° C., the temperature increase of thesemiconductor wafer support structure increasing the temperature of thesemiconductor wafer.
 33. An apparatus for removing a patternedphotoresist layer from a semiconductor wafer as recited in claim 31,wherein the power supply is configured to supply the microwave powerwithin a range extending from about 500 Watts to about 5000 Watts. 34.An apparatus for removing a patterned photoresist layer from asemiconductor wafer, comprising: a chamber having an internal region,the internal region being defined by a top, a bottom, and sides; asemiconductor wafer support structure disposed in close proximity to thebottom of the chamber internal region, the semiconductor wafer supportstructure configured to hold a semiconductor wafer having a patternedphotoresist layer; a electrically conductive coil disposed above the topof the chamber internal region; an H₂O vapor supply line configured tosupply H₂O vapor to the chamber internal region; a first power supplyconfigured to supply radio frequency power to the coil, the radiofrequency power supplied to the coil being used to induce an electriccurrent in the chamber internal region, the induced electric currenttransforming the H₂O vapor into H ions, H radicals, O ions, and Oradicals; and a second power supply configured to supply radio frequencypower to the semiconductor wafer support structure, the radio frequencypower causing the semiconductor wafer support structure to have a biasvoltage, the bias voltage attracting the H ions and the O ions to thepatterned photoresist layer of the semiconductor wafer, wherein the Hions and the O ions react to remove at least a portion of the patternedphotoresist layer.
 35. An apparatus for removing a patterned photoresistlayer from a semiconductor wafer as recited in claim 34, furthercomprising: a heater configured to increase the temperature of thesemiconductor wafer support structure within a temperature range fromabout 25° C. to about 130° C., the temperature increase of thesemiconductor wafer support structure increasing the temperature of thesemiconductor wafer.
 36. An apparatus for removing a patternedphotoresist layer from a semiconductor wafer as recited in claim 34,wherein the first power supply is configured to supply radio frequencypower within a range extending from about 500 Watts to about 3000 Watts.37. An apparatus for removing a patterned photoresist layer from asemiconductor wafer as recited in claim 34, wherein the second powersupply is configured to supply radio frequency power within a rangeextending from about 0 Watts to about 800 Watts.